docs: def resource_headers(self, jobscript):
          """Given a :class:`~clusterjob.JobScript` instance, return a list of
          lines that encode the resource requirements, to be added at the top of
          the rendered job script
          """
          lines = []
          for (key, val) in jobscript.resources.items():
              if key in self.resource_replacements:
                  slurm_key = self.resource_replacements[key]
                  val = str(val).strip()
              else:
                  slurm_key = key
              if not slurm_key.startswith('-'):
                  if len(slurm_key) == 1:
                      slurm_key = '-%s' % slurm_key
                  else:
                      slurm_key = '--%s' % slurm_key
              if val is None:
                  continue
              if type(val) is bool:
                  if val:
                      lines.append("%s %s" % (self.prefix, slurm_key))
              else:
                  if slurm_key.startswith('--'):
                      lines.append('%s %s=%s'
                                    % (self.prefix, slurm_key, str(val)))
                  else:
                      lines.append('%s %s %s'
                                   % (self.prefix, slurm_key, str(val)))
          return lines